By default Brocade SAN switches have the Telnet protocol enabled, you may wish to disable this as part of security hardening of your devices to mitigate to the session being transmitted in clear text and enforce SSH connectivity as the management protocol.

In order to disable the Telnet protocol you will be required to modify the IP filter policy to disable inbound connectivity to the TCP service port, which can be performed using the Fabric OS CLI.

As the default IP filter policy cannot be modified, in order to modify the rules an IP filter policy is required to be created by cloning the default policy.

Once we have cloned the default policies we will be required to remove the existing rule to permit connectivity on TCP service port 23. By invoking the command ‘ipfilter –show’, we can determine the current rule number which permits the connectivity.